Consumption of whole grains and legumes modulates the genetic effect of the APOA5 -1131C variant on changes in triglyceride and apolipoprotein A-V concentrations in patients with impaired fasting glucose or newly diagnosed type 2 diabetes

1 Department of Food and Nutrition, College of Human Ecology, National Leading Research Laboratory of Clinical Nutrigenetics/Nutrigenomics, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Korea

Abstract

Background

The apolipoprotein A5 gene (APOA5) -1131 T > C polymorphism is associated with mild hypertriglyceridemia in type 2
diabetic subjects, and interacts with dietary fat in the determination of triglyceride
concentrations. We examined whether a substitution of whole grains and legumes for
refined rice in a high carbohydrate diet (about 65% of energy derived from carbohydrate)
may modify the effect of this variant on changes in apolipoprotein A-V (apoA-V) and
triglyceride concentrations.

Methods

We genotyped the APOA5 -1131 T > C in individuals with impaired fasting glucose (IFG) or newly diagnosed
type 2 diabetes, who were randomly assigned to either a group ingesting whole grain
and legume meals daily or a control group for 12 weeks.

Results

After dietary intervention, we observed significant interactions between the APOA5 -1131 T > C polymorphism and carbohydrate sources (whole grains and legumes versus
refined rice) in the determination of mean percent changes in triglyceride and apoA-V
(P interactions <0.001 and =0.038, respectively). In the refined rice group (n = 93), the carriers of the risk C allele (n = 50) showed a greater increase in the mean percent changes of triglyceride and apoA-V
than noncarriers after adjusting for HOMA-IR (P = 0.004 and 0.021, respectively). The whole grain and legume group (n = 92), however, showed a decrease in fasting glucose, HOMA-IR, and triglyceride,
and an increase in apoA-V, irrespective of genotype.

Conclusions

The data showed that the magnitude of the genetic effect of the APOA5 -1131C variant on triglyceride and apoA-V levels was modulated when substituting
consumption of whole grains and legumes for refined rice as a carbohydrate source
in IFG or diabetic subjects.